Nutrients & electrolytes
Measured in ng/mL.
Ferritin is the protein the body uses to store iron, and the amount circulating in blood is proportional to how much iron is held in reserve. It is the single most useful test for detecting iron deficiency, because stores fall long before haemoglobin does — a person can be substantially iron-depleted, with the fatigue, hair shedding, breathlessness and poor exercise recovery that go with it, while their haemoglobin and full blood count still read normal. That is the phase a standard anaemia screen misses entirely. Ferritin has one important complication: it is also an acute-phase reactant, meaning it rises during inflammation or infection regardless of iron status. A normal ferritin alongside a raised hs-CRP can therefore conceal genuine deficiency, which is why the two are always read together.
Ferritin falls long before haemoglobin does, so iron deficiency is routinely missed by a normal blood count.
Ferritin is an acute-phase reactant and rises with inflammation, so it must be read alongside hs-CRP.
Symptomatic improvement is generally seen above 50 ng/mL, well above the 15 ng/mL where many lab ranges begin.
A high ferritin most often reflects inflammation, infection, liver disease or heavy alcohol use rather than iron overload. Genuine iron overload, including haemochromatosis, does raise it and is confirmed with transferrin saturation rather than ferritin alone. A raised ferritin with a raised hs-CRP usually points to the inflammation.
A low ferritin means depleted iron stores and is the earliest reliable sign of iron deficiency. Symptoms — fatigue, poor concentration, hair thinning, breathlessness on exertion, restless legs — often appear well before anaemia. In anyone menstruating this is common; in men and post-menopausal women it needs the source of loss investigated.
| Band | Value |
|---|---|
| Iron deficiency | < 30 ng/mLBelow 15 ng/mL is diagnostic; symptoms commonly appear under 30 |
| Suboptimal stores | 30 – 50 ng/mL |
| Adequate | 50 – 150 ng/mL |
| Raised | > 200 ng/mLInterpret alongside hs-CRP before concluding iron overload |
Laboratory intervals vary. Interpret with a physician.
Iron deficiency is among the most common nutritional deficiencies in India, particularly in women of reproductive age, and predominantly vegetarian diets supply iron in the non-haem form, which is absorbed considerably less efficiently. Iron deficiency also distorts HbA1c upward, which can push someone across a diabetes threshold on the basis of an iron problem.
hs-CRP is a high-sensitivity measurement of C-reactive protein, a substance the liver releases in response to inflammation.
HbA1c measures the proportion of haemoglobin in your red blood cells that has sugar attached to it.
Vitamin B12 is required for red blood cell formation, DNA synthesis and the maintenance of the myelin sheath around nerves.
Low ferritin in a man or a post-menopausal woman should always be discussed with a physician, since it raises the question of where iron is being lost. Do not begin iron supplementation without medical advice: it is unhelpful where the cause is inflammation and harmful in undiagnosed iron overload.
Yes, and this is the most common way iron deficiency is missed. Haemoglobin falls only once stores are largely exhausted, so ferritin can be low — with all the accompanying symptoms — while a full blood count reads entirely normal.
Because ferritin rises with inflammation independently of iron. Without a simultaneous inflammatory marker, a normal ferritin in someone with ongoing inflammation can hide real deficiency. The pair is interpretable; ferritin alone often is not.
Laboratory ranges often start as low as 15 ng/mL, but symptomatic improvement in fatigue and exercise capacity is generally seen at levels above 50 ng/mL. The target is a clinical judgement your physician makes with the rest of the panel, not a fixed number.
The programme
Peak Brain draws a full blood and urine panel at your home, has a licensed physician read every marker together rather than one at a time, and turns what they find into a ranked 90-day protocol with a retest at the end.
Authorship & review
Written by the Peak Brain clinical team. Assigned clinical reviewer: Dr. RS Pradhan, MD — review pending; this page has not yet been signed off.
Published . Last updated .
This page is general health information, not medical advice, diagnosis or treatment. Reference ranges vary between laboratories. Never delay or disregard advice from a qualified health professional because of something you read here. If you think you may have a medical emergency, call your local emergency number.